[c-nsp] PIX-virus-DoS-connection problem

[Marcelo Maraboli]

Rick

The anti-spoof feature is not through ACLs, but an Internal PIX
feature in 6.2(2):

ip verify reverse-path interface outside
ip verify reverse-path interface inside

and yes, I do have turbo-acl activated.

regards,

Cheung, Rick wrote:
>         Do you have TurboACL configured for the anti-spoof ACLs you 
> mentioned?
> 
>         That should help cap CPU consumption.
> 
> 
> 
> Rick Cheung
> 
> -----Original Message-----
> From: Marcelo Maraboli [mailto:marcelo.maraboli at usm.cl]
> Sent: Thursday, November 11, 2004 11:02 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] PIX-virus-DoS-connection problem
> 
> 
> Hello Admins
> 
> We have 2 525 PIX in failover mode with an unexpected behavior.
> 
> Yesterday, a virus/worm (probably a Kazaa worm) infected one of
> our PC ans started to generate 48 IP spoofed packets per second to
> a list of destinations (I suppose other Kazaa members).
> 
> Since our PIX is configured to drop Spoofed IP packets on the
> Inside and Outside interfaces, the CPU went up to 92% and the
> number of "active connections" was increasing at a linear rate.
> 
> Even though this traffic did not reach the border router, these
> packets were indeed dropped by the PIX, but the number of connections
> and CPU were NOT NORMAL.
> 
> After we unpluged the infected PC, the PIX CPU went back to
> normal, but the number of active connections (reported by SNMP)
> still was rising. I waited more than 1 hour (default idle connection
> timeout) and still nothing...
> 
> I have this graphed at:
> http://elqui.dcsc.utfsm.cl/tmp/Cisco%20PIX%20525%20Primary-Active.htm
> 
> we are using PIX version 6.2(2). Using PDM I graphed the CPU
> and number of connections at:
> 
> http://elqui.dcsc.utfsm.cl/tmp/conn.jpg
> http://elqui.dcsc.utfsm.cl/tmp/cpu.jpg
> 
> Is this a PIX malfunction and does not reset the SNMP
> connections counters ?? (since the PDM graph differs)
> 
> anyone else experienced this ?
> 
> thanks,
> -- 
> Marcelo Maraboli Rosselott
> Jefe Area de Redes y Comunicaciones (Network & UNIX Systems Engineer)
> Ingeniero Civil Electronico                     (Electronic Engineer)
> 
> Direccion Central de Servicios Computacionales (DCSC)
> Universidad Tecnica Federico Santa Maria, Chile.
> phone: +56 32 654237
> mailto: marcelo.maraboli @ usm.cl       http://elqui.dcsc.utfsm.cl/
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-- 
Marcelo Maraboli Rosselott
Jefe Area de Redes y Comunicaciones (Network & UNIX Systems Engineer)
Ingeniero Civil Electronico                     (Electronic Engineer)

Direccion Central de Servicios Computacionales (DCSC)
Universidad Tecnica Federico Santa Maria, Chile.
phone: +56 32 654237
mailto: marcelo.maraboli @ usm.cl	http://elqui.dcsc.utfsm.cl/